Anti-Doping Norway said in a statement on Wednesday that Johaug, who has also won three Olympic medals including gold at the 2010 Games in Vancouver, had been provisionally suspended until Dec. 18.
Johaug said the positive test for the steroid clostebol was caused by a cream she was given in Italy by Norwegian team doctor Fredrik Bendiksen to treat a sunburnt lip.
"The reason for the decision is that the disciplinary committee is of the opinion that the athlete cannot be said to have acted without fault," Anti-Doping Norway's Anstein Gjengdal said in the statement.
"The suspension means that the athlete cannot compete or take part in organised training sessions," Gjengdal said, adding that the committee had so far only considered if Johaug should be provisionally suspended, and not made a decision about the case itself.
The statement from Anti-Doping Norway said that Bendiksen's role in the failed test would also be investigated.
The 28-year-old Johaug said in a statement issued by the Norwegian Skiing Federation that the decision to suspend her was tough to take, but she accepted it.
"I am now going to concentrate on what is most important, a full exoneration," she said.
(Reporting by Philip O'Connor in Stockholm; Editing by Toby Davis)
